1. Field of the Invention
The present invention relates to a peptide having bone tissue regeneration capacity and specifically binding to a surface of apatite mineral, and more particularly, to a peptide having bone tissue regeneration capacity and specifically binding to a surface of apatite mineral, capable of being stably immobilized to the surface of apatite mineral to retain effective activity and exhibit bone regeneration effects for a long time, by linking an amino acid sequence having bone tissue regeneration capacity and an amino acid sequence having apatite-binding capacity to each other to thereby provide a peptide having both bone-forming effects and binding capacity to the surface of apatite mineral, and a composition for bone tissue regeneration, containing the peptide.
2. Background of the Related Art
Bones and teeth are called hard tissue in the body. Bones are composed of roughly 45% of bone inorganic materials, 35% of organic materials, and 20% of water. As for the tooth, enamel has about 97% inorganic material, dentin has 70% inorganic material, and cementum has 50% inorganic material. The inorganic material content is somewhat different depending on the animal species, body part, age, and the like.
Of the constituent materials, most of the organic materials are collagen, which is involved in generating bones and maintaining toughness and elasticity of the bones, and is present as a matrix that induces selective adhesion of bone cells to thereby orient bone inorganic particles. Apatite mineral is a main component of the bone in a natural state, that is, the bone inorganic materials of a vertebrate, and has been known as hydroxyapatite (Ca10(PO4)6(OH)2), hydroxylapatite, carbonated hydroxy apatite (CHAp, A-type: Ca10(PO4)6[(OH)2-2x(CO3)x], B-type: Ca10-x[(PO4)6-2x (CO3)2x](OH)2). It has been known that a tiny amount of Mg2+, Na+, or K+ is contained instead of Ca2+, and a tiny amount of Cl− or F− is contained instead of OH−. Therefore, studies that dental materials and bone graft materials for healing bone defects are made of apatite mineral or the surfaces thereof are coated with apatite mineral have been conducted.
The purpose of bone graft is to restore morphological and physiological functions of the bone to thereby maintain biomechanical roles. Hence, the apatite bone graft material used here needs to satisfy fundamental conditions, such as, being instantly used, having no immune responses, promoting fast bone generation and revascularization, maintaining bone support and continuity, and the like. However, apatite itself may serve as a mediator that has bone conductivity, but has no bone induction capacity for initial bon morphogenesis, which is needed to shorten the duration of treatment. In order to make up for this fault, studies that a biologically active substance having chemotactin, such as extracellular matrix protein, tissue growth factor, or bone morphogenetic protein, is used together with apatite were done, and products such as INFUSE (containing BMP-2), GEM21S (containing PDGF), and the like, were developed. However, these proteins are not stably immobilized on a surface of the apatite and released from the apatite, and then exposed to the systemic blood and thus be degraded, and therefore, activities of these proteins are difficult to maintain on the surface of the apatite for bone regeneration effect. Hence, a material which is stably immobilized on the surface of apatite to thereby retain effective activity is needed in order to increase the bone regeneration effect.
The present inventors made an effort to solve the problems of the related art as described above. As a result, the present inventors confirmed that a peptide having both bone-forming capacity and binding capacity to apatite mineral can be present in a stable state when binding to a surface of apatite mineral, can promote transition, proliferation, and differentiation of cells associated with regeneration and eventually maximize bone tissue regeneration capacity, and exhibit high therapeutic effects in bone tissue regeneration, and then completed the present invention.